Tutorials
Example of Test Driven Development with C++ and Google Test
To develop a software based on “Test Driven Development” one should follow the following steps:
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1)Write enough failing Test Code (include compile time and run time failures) 2)Write Production code to pass the failing tests. 3)Refactor the production code and verify the same with existing test. 4)Go to step 1 |
so let say we want to develop a binary search tree, here I’m using Google Test. Step 1, Write enough failing Test Code so the first step would be something like this:
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class testingTree: public ::testing::Test { protected: testingTree(){} ~testingTree(){} void SetUp(){} void TearDown(){} }; TEST_F(testingTree,makeTree) { std::shared_ptr<Tree> tree=makeTree(); EXPECT_NE(tree.get(),nullptr); } int main(int argc, char ** argv) { testing::InitGoogleTest(&argc, argv); return RUN_ALL_TESTS(); } |
Step 2, Write Production code to …
Example of Test Driven Development with C++ and Google Test Read More »
Standard Exception Handler in C++ and Custom Exception Handler with Examples
Exception handling
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try { some code } catch (Exception e) { throw e; } catch (...)//... will catch any exception { throw; } |
C++ Standard Exceptions
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1)std::bad_alloc 2)std::bad_cast 3)std::bad_exception 4)std::bad_typeid 5)std::logic_error 5-1)std::domain_error: exception thrown when a mathematically invalid domain is used. 5-2)std::invalid_argument 5-3)std::length_error 5-4)std::out_of_range 6)std::runtime_error: An exception that theoretically cannot be detected by reading the code. 6-1)std::overflow_error : The only standard library components that throw std::overflow_error are std::bitset::to_ulong and std::bitset::to_ullong. 6-2)std::underflow_error 6-3)std::range_error |
List of Example
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struct Foo { virtual ~Foo() {} }; struct Bar { virtual ~Bar() {} }; void bad_allocExample() { try { while (true) { new int[100000000ul]; } } catch (const std::bad_alloc& e) { std::cout << "Allocation failed: " << e.what() << '\n'; } } void bad_castExample() { Bar b; try { Foo& f = dynamic_cast<Foo&>(b); } catch(const std::bad_cast& e) { std::cout << e.what() << '\n'; } } void bad_typeidExample() { Foo* p = nullptr; try { std::cout << typeid(*p).name() << '\n'; } catch(const std::bad_typeid& e) { std::cout << e.what() << '\n'; } } void logical_ErrorExample() { int amount, available; amount=10; available=9; if(amount>available) { throw std::logic_error("Error"); } catch ( std::exception &e ) { std::cerr << "Caught: " << e.what( ) << std::endl; std::cerr << "Type: " << typeid( e ).name( ) << std::endl; }; } void domain_errorExample() { try { const double x = std::acos(2.0); std::cout << x << '\n'; } catch (std::domain_error& e) { std::cout << e.what() << '\n'; } catch (...) { std::cout << "Something unexpected happened" << '\n'; } } void invalid_argumentExample() { try { // binary wrongly represented by char X std::bitset<32> bitset(std::string("0101001X01010110000")); } catch (std::exception &err) { std::cerr<<"Caught "<<err.what()<<std::endl; std::cerr<<"Type "<<typeid(err).name()<<std::endl; } } void length_errorExample() { try { // vector throws a length_error if resized above max_size std::vector<int> myvector; myvector.resize(myvector.max_size()+1); } catch (const std::length_error& le) { std::cerr << "Length error: " << le.what() << '\n'; } } void out_of_rangeExample() { std::vector<int> myvector(10); try { myvector.at(20)=100; // vector::at throws an out-of-range } catch (const std::out_of_range& oor) { std::cerr << "Out of Range error: " << oor.what() << '\n'; } } void overflow_errorExample() { try { std::bitset<100> bitset; bitset[99] = 1; bitset[0] = 1; // to_ulong(), converts a bitset object to the integer that would generate the sequence of bits unsigned long Test = bitset.to_ulong(); } catch(std::exception &err) { std::cerr<<"Caught "<<err.what()<<std::endl; std::cerr<<"Type "<<typeid(err).name()<<std::endl; } } void range_errorExample() { try { throw std::range_error( "The range is in error!" ); } catch (std::range_error &e) { std::cerr << "Caught: " << e.what( ) << std::endl; std::cerr << "Type: " << typeid( e ).name( ) << std::endl; } } //Defining your exceptions struct CustomException : public std::exception { const char * what () const throw () { return "CustomException happened"; } }; void customExceptionExample() { try { throw CustomException(); } catch(CustomException& e) { std::cout << "CustomException caught" << std::endl; std::cout << e.what() << std::endl; } catch(std::exception& e) { //Other errors } } |
Finding Memory leaking, Stack and Heap overflow
When you access an array index, C and C++ don’t do bound checking. Segmentation faults only happen when you try to read or write to a page that was not allocated (or try to do something on a page which isn’t permitted, e.g. trying to write to a read-only page), but since pages are usually …
